(PID+算法(c语言)

1、PID 算法（c语言BC31 TC30 编译过，可运行。#include <stdio.h>#include<math.h>struct _pid int pv; /*integer that contains the process value*/ int sp; /*integer that contains the set point*/ float integral; float pgain; float igain; float dgain; int deadband; int last_error;struct _pid warm,*pid;int proc

2、ess_point, set_point,dead_band; float p_gain, i_gain, d_gain, integral_val,new_integ; /*- pid_init DESCRIPTION This function initializes the pointers in the _pid structure to the process variable and the setpoint. *pv and *sp are integer pointers. -*/ void pid_init(struct _pid *warm, int process_poi

3、nt, int set_point) struct _pid *pid; pid = warm; pid->pv = process_point; pid->sp = set_point; /*- pid_tune DESCRIPTION Sets the proportional gain (p_gain), integral gain (i_gain), derivitive gain (d_gain), and the dead band (dead_band) of a pid control structure _pid. -*/ void pid_tune(struct

4、 _pid *pid, float p_gain, float i_gain, float d_gain, int dead_band) pid->pgain = p_gain; pid->igain = i_gain; pid->dgain = d_gain; pid->deadband = dead_band; pid->integral= integral_val; pid->last_error=0; /*- pid_setinteg DESCRIPTION Set a new value for the integral term of the p

5、id equation. This is useful for setting the initial output of the pid controller at start up. -*/ void pid_setinteg(struct _pid *pid,float new_integ) pid->integral = new_integ; pid->last_error = 0; /*- pid_bumpless DESCRIPTION Bumpless transfer algorithim. When suddenly changing setpoints, or

6、when restarting the PID equation after an extended pause, the derivative of the equation can cause a bump in the controller output. This function will help smooth out that bump. The process value in *pv should be the updated just before this function is used. -*/ void pid_bumpless(struct _pid *pid)

7、pid->last_error = (pid->sp)-(pid->pv); /*- pid_calc DESCRIPTION Performs PID calculations for the _pid structure *a. This function uses the positional form of the pid equation, and incorporates an integral windup prevention algorithim. Rectangular integration is used, so this function must

8、be repeated on a consistent time basis for accurate control. RETURN VALUE The new output value for the pid loop. USAGE #include "control.h"*/ float pid_calc(struct _pid *pid) int err; float pterm, dterm, result, ferror; err = (pid->sp) - (pid->pv); if (abs(err) > pid->deadband)

9、 ferror = (float) err; /*do integer to float conversion only once*/ pterm = pid->pgain * ferror; if (pterm > 100 | pterm < -100) pid->integral = 0.0; else pid->integral += pid->igain * ferror; if (pid->integral > 100.0) pid->integral = 100.0; else if (pid->integral <

10、 0.0) pid->integral = 0.0; dterm = (float)(err - pid->last_error) * pid->dgain; result = pterm + pid->integral + dterm; else result = pid->integral; pid->last_error = err; return (result); void main(void) float display_value; int count=0; pid = &warm;/ printf("Enter the va

11、lues of Process point, Set point, P gain, I gain, D gain n");/ scanf("%d%d%f%f%f", &process_point, &set_point, &p_gain, &i_gain, &d_gain); process_point = 30; set_point = 40; p_gain = (float)(5.2); i_gain = (float)(0.77); d_gain = (float)(0.18); dead_band = 2; inte

12、gral_val =(float)(0.01); printf("The values of Process point, Set point, P gain, I gain, D gain n"); printf(" %6d %6d %4f %4f %4fn", process_point, set_point, p_gain, i_gain, d_gain); printf("Enter the values of Process pointn"); while(count<=20) scanf("%d",&process_point); pid_init(&warm, process_point, set_point); pid_tune(&warm, p_gain,i_gain,d_gain,dead_band); pid_setinteg(&warm,0.0); /pid_setinteg(&warm,30.0); /Get input value for process point pid